Resumen
Nipple rubber is an important part of a milking machine, one of its key elements. This is the only component of a milking plant that has direct contact with the surface of a cow udder. In addition, nipple rubber is the most loaded component of a milking machine. During the milking process, it is compressed and unclenched more than 400 times. In order to maximize the effect of the use of rubber, it is necessary to calculate the conditions of its use correctly, to monitor technical parameters in due time. The task of the study is to establish changes in the technical parameters of the nipple rubber of milking machines and their impact on the performance of the article.In the course of the research, it was established that the service life of all kinds of nipple rubbers was 1,000 hours, which, if used for 8 hours a day, corresponds to 125 days or 4 months of operation. When used for 1,000 hours, the rubber stiffness varies within significant limits and an average is: for products made of silicone 2,849.61±52.23?3,343.76±51.26 N/m; made of the material of rubber mixtures ? 2,597.76±78.26?2,821.43±55.24 N/m. The readiness coefficient of all products is 1. Using electron microscopy, it was possible to establish the changes of the inner surface of nipple rubber after operating for 125 days/1,000 hours and after operating for 250 days/2,000 hours. It is proved that all its basic parameters change during operation. The weight of an article changes by 8.5 %, the depth ? by 37 %, the wall thickness ? by 2.5 %, and the stretching length ? by 27 %. The high positive correlation dependence (r=+0.939) between the nipple rubber stiffness and milking intensity was found.The studied indicators are important for determining the performance and nipple rubber suitability for use. The conducted research offers a real possibility of taking into consideration the qualitative parameters of nipple rubber during their selection and subsequent operation